TWI412983B - Detecting method of performing multi-touch on a capacitive touch panel - Google Patents

Abstract

While detecting touch points on a capacitive touch panel, unnecessary intersection points are first abandoned with the aid of a high processing efficiency introduced by self capacitance detecting techniques, so as to avoid processing unnecessary data. Then candidate touch points generated by applying the self capacitance detecting techniques are precisely detected by applying mutual capacitance detecting techniques, so as to rapidly performing true multi-touch, and so as to overcome insufficient precision in applying the self capacitance techniques and tardy processing efficiency in applying the mutual capacitance techniques on a conventional capacitive touch panel.

Description

Multi-touch detection method on capacitive touch panel

The present invention discloses a method for detecting multi-touch on a capacitive touch panel, in particular, a self-capacity (Self Capacitance) detection and a mutual capacitance (Mutual Capacitance) detection in cooperation with a capacitive touch. Multi-touch detection method on the control panel.

A capacitive touch panel generally used for a touch device is mainly composed of a glass substrate, and is coated on the glass substrate with a set of horizontally arranged sensing lines and a set of vertically arranged sensing lines, wherein the set of horizontal sensing lines and the A plurality of staggered points are formed on the glass substrate between the sets of vertical sensing lines. When the user of the touch device approaches the touch panel with a finger, the capacitance between the horizontal sensing line and the vertical sensing line is changed at the staggered point (also referred to as a contact point) that the touch device contacts; A capacitance sensing driver (Charge Sensing Driver) may be additionally provided to sense the change of capacitance between the horizontal sensing line and the vertical sensing line to determine whether it is touched by the user's finger and decide to use according to the movement mode touched by the user. The instruction that the person wants to trigger.

The prior art has Self Capacitance detection and Mutual Capacitance detection. Two detection technologies for capacitive touch panels are used to confirm that the user is using a finger on the capacitive touch panel. The touch point that is triggered (Touch Point). Please refer to FIG. 1 , which is a partial schematic diagram for explaining a mutual capacitance detection technology implemented on a capacitive touch panel 100 . The vertical lines indicated as X1, X2, X3, X4, and X5 represent partial vertical sensing lines on the capacitive touch panel 100, and the horizontal lines indicated as Y1, Y2, Y3, Y4, and Y5 represent capacitive touch panels. A part of the horizontal sensing line on the 100, the icon of the finger represents the actual touch of the user on the capacitive touch panel 100, and the plurality of real points P1, P2, and P3 located at the intersection of the horizontal sensing line and the vertical sensing line. Represents the contact points detected on the capacitive touch panel 100 by mutual capacitance detection technology. As shown in FIG. 1 , when the mutual capacitance detection technology is implemented in the capacitive touch panel shown in FIG. 1 , a reset signal is sequentially sent to the horizontal sensing lines Y1 - Y5 in order to sequentially correspond. The horizontal sensing line is pulled up to a predetermined potential, and the capacitance change is sensed on the vertical sensing lines X1-X5 in order to detect an accurate contact point on the capacitive touch panel 100. For example, when the reset signal is sent to the horizontal sensing line Y2, the horizontal sensing line Y2 is filled with electric charge, and the vertical sensing lines X1-X5 are detected in turn, and the capacitance is sensed in the vertical sensing lines X2 and X4. The capacitive touch panel 100 can determine the capacitance changes at the two intersections of the horizontal sensing line Y2 and the vertical sensing lines X2 and X4 to determine the contact points P1 and P2. . Similarly, when the reset signal is sent to the horizontal sensing line Y4, the capacitive touch panel 100 only detects the change in capacitance at an intersection of the horizontal sensing line Y4 and the vertical sensing line X4, and determines the contact point P3. . Therefore, the mutual capacitance detection technology can be used to achieve accurate touch point detection, which is called true multi-touch technology; however, due to the need for horizontal sensing lines Y1-Y5 and vertical sensing lines X1 -X5 performs potential reset and detection individually in sequential scanning mode, which makes the capacitive touch panel 100 time-consuming to detect multi-touch contact points. Therefore, the mutual capacitance detection technology is not suitable for large size. A capacitive touch panel containing a large number of vertical/horizontal sensing lines.

Different from the mutual-capacity detection technology, the self-capacitance detection technology performs the detection of the contact points in a relatively fast manner, so that the capacitive touch panel 100 can meet the needs of the user in real-time touch. Please refer to FIG. 2 , which is a partial schematic diagram for explaining the implementation of the self-capacitance detection technology on the capacitive touch panel 100 . The label of FIG. 2 follows the first diagram, and therefore no further description is provided. As shown in FIG. 2, when the self-capacitance detection technology is implemented in the capacitive touch panel shown in FIG. 1, the plurality of reset signals are simultaneously sent to the horizontal sensing lines Y1-Y5 to all the horizontal sensing. The line is pulled up to a first predetermined potential, and at the same time, the capacitance sensing of the vertical sensing lines X1-X5 is performed on the vertical sensing lines X1-X5 to find the capacitance change in the vertical sensing lines X1-X5. Vertical sensing line; next, the potential of all horizontal sensing lines will be reduced to zero, and a plurality of reset signals will be simultaneously sent to the vertical sensing lines X1-X5 to pull all vertical sensing lines to a second predetermined The potential is simultaneously sensed on the horizontal sensing lines Y1-Y5; thus, the capacitive touch panel 100 will know which vertical sensing lines and which horizontal sensing lines are triggered. In the same example of the actual contact point distribution as in FIG. 1, after the horizontal sensing lines Y1-Y5 are pulled up to the first predetermined potential, the capacitive touch panel 100 detects the capacitance on the vertical sensing lines X2 and X4. Change; then, when the potential of the horizontal sensing line Y1-Y5 is pulled down to zero, and the vertical sensing line X1-X5 is pulled up to the second predetermined potential, the capacitive touch panel 100 detects the horizontal sensing line Y2 The capacitance on Y4 changes. As a result of the capacitance changes on the vertical sensing lines X2, X4 and the horizontal sensing lines Y2, Y4, the capacitive touch panel 100 determines a plurality of intersections on the horizontal sensing lines Y2, Y4 and the vertical sensing lines X2, X4. The contact points P1, P2, P3, and P4 are obtained. However, in essence, the user only triggers the contact points P1, P2, and P3, and does not touch the contact point P4 detected when the self-capacitance detection technology is implemented; this is because the self-capacity detection technology is essentially simultaneous detection. Measure all the vertical sensing lines or simultaneously detect all horizontal sensing lines to determine the contact point triggered by the user, and accordingly achieve a higher detection speed than the mutual capacitance detection technology, but also sacrifice part of the accuracy Degree, and a misjudgment of the contact point P4 as shown in Fig. 2 is generated. In other words, since the self-capacitance detection technology does not actually detect the intersection of each sensing line on the capacitive touch panel 100 when the mutual capacitance detection technology is implemented, it may not satisfy the true multipoint. The need for touch.

The invention discloses a method for detecting multi-touch on a capacitive touch panel. The method includes resetting a plurality of first sensing lines of a capacitive touch panel to a first potential; and when resetting the plurality of first sensing lines to the first potential, detecting and detecting the plurality of first sensing lines Detecting a change in capacitance of the plurality of second sensing lines; resetting the plurality of second sensing lines to a second potential; and detecting the plurality of second sensing lines to the second potential a change in capacitance of the first sensing line; generating a plurality of candidate contact points according to a result of detecting a change in capacitance of the plurality of first sensing lines and a change in capacitance of the plurality of second sensing lines; and sequentially resetting the plurality of sensing points a plurality of first sensing lines of the candidate contact points, and detecting a plurality of first sensing lines covering the plurality of candidate contact points, detecting a capacitance change of the plurality of second sensing lines to be used by the plurality Find a plurality of actual contact points among the candidate contact points.

In order to solve the problem that the detection speed of the capacitive touch panel is too slow or the detection result is misjudged when the self-capacitance detection technology or the mutual capacitance detection technology is applied in the prior art, the present invention discloses a capacitive touch. Multi-touch detection method on the control panel. The method utilizes both self-capacitance detection technology and mutual capacitance detection technology, and successfully overcomes the disadvantages of both, so that the capacitive touch panel using the multi-touch detection method of the present invention can be simultaneously provided. The advantages of self-contained detection technology and mutual capacitance detection technology in detecting speed and detecting the accuracy of the result.

In the method disclosed in the present invention, when the user's finger touches the capacitive touch panel, firstly, in the first stage, the self-capacity detection technology is used to find at least one possible on the capacitive touch panel. The candidate touch point (Candidate touch point), in a second stage, uses the mutual capacitance detection technology to detect the capacitance change of the candidate contact points one by one with the mutual capacitance detection technology to accurately find the capacitive touch All actual touch points on the panel.

Please refer to FIG. 3 , which is a flowchart of a method for detecting multi-touch on a capacitive touch panel according to the present invention. As shown in FIG. 3, the present invention includes the following steps: Step 302: reset a plurality of first sensing lines of a capacitive touch panel to a first potential; Step 304: When resetting the plurality of first sensing And detecting a change in capacitance of the plurality of second sensing lines interleaved with the plurality of first sensing lines; and step 306: resetting the plurality of second sensing lines of the capacitive touch panel to the first sensing line a second potential; step 308: detecting a change in capacitance of the plurality of first sensing lines interleaved with the second sensing line when the second sensing line is reset to the second potential; step 310: detecting the complex number a plurality of candidate contact points are generated as a result of a change in capacitance of the first sensing line and a capacitance change of the second sensing line; step 312: resetting a first sensing line covering one of the plurality of candidate contact points, and sequentially Detecting a change in capacitance of the plurality of second sensing lines to find out whether there is a contact point on the first sensing line; Step 314: Confirming whether all of the first sensing lines covering the plurality of candidate contact points are in the plural Second sense line The detection of the change of the capacitance is completed; when all the first sensing lines covering the plurality of candidate contact points have been detected on the second sensing line of the plurality of sensing lines, step 316 is performed, otherwise step 312 is performed; And step 316: correspondingly detecting the capacitance change result of the plurality of first sensing lines covering the plurality of candidate contact points on the second sensing line of the plurality of candidate contact points, and finding a plurality of the plurality of candidate contact points Actual contact points.

Steps 302 to 310 are the first stage of the present invention, that is, using the self-capacitance detection technology for the capacitive touch panel 100; and steps 312 to 316 are the second phase of the present invention, that is, using The mutual capacitance detection technology is applied to the capacitive touch panel 100. The following related explanations will be based on the diagram in Figure 2.

In the first stage of the method disclosed in the present invention, first, in step 302, the potentials of all the horizontal sensing lines Y1-Y5 included in the capacitive touch panel 100 are pulled up to a first potential in a reset manner, and In step 304, the capacitance change detection is performed on all the vertical sensing lines X1-X5 included in the capacitive touch panel 100 to determine which of the vertical sensing lines X1-X5 are triggered by the user. Then, in step 306, the potentials of all the vertical sensing lines X1-X5 included in the capacitive touch panel 100 are pulled up to a second potential in a reset manner, and are simultaneously included in the capacitive touch panel 100 in step 308. All of the horizontal sensing lines Y1-Y5 perform capacitance change detection to determine which of the horizontal sensing lines Y1-Y5 are triggered by the user. In step 310, all intersections between all the horizontal sensing lines and the vertical sensing lines that are detected by step 304 and step 308 to produce a change in capacitance are determined as a plurality of candidate contact points. In the touch point triggered by the user shown in FIG. 2, the candidate contact points determined after the execution of steps 302 to 310 are P1, P2, P3, and P4.

In the second phase of the method disclosed by the present invention, the range of sensing lines detected by the mutual capacitance detecting technique is limited to a plurality of vertical sensings of a plurality of candidate contact points detected in the first stage. The line and the horizontal sensing line, instead of the carpet detection of all the sensing lines on the capacitive sensing panel 100 as in the prior art, can reduce the amount of processing data, save a lot of processing time, And use the mutual capacitance detection technology to accurately find the characteristics of the contact points. In step 312, one of the horizontal sensing lines Y1-Y5 has a horizontal sensing line covering the candidate contact point, and sequentially detects the capacitance changes of all the vertical sensing lines interlaced with the same. By the recursive steps formed by steps 312 and 314, all the horizontal sensing lines covering the candidate contact points in the horizontal sensing lines Y1-Y5 can be detected on the vertical sensing lines of the interlaced vertical sensing lines, and can be detected according to All of the capacitance changes obtained in steps 312, 314 are eliminated from the plurality of candidate contact points determined in step 310 by the misjudged candidate contact points, leaving the contact points actually triggered by the user. For example, assume that, as shown in FIG. 2, after the first plurality of candidate contact points obtained after performing the first stage of the method of the present invention are P1, P2, P3, and P4, then in step 312, the horizontal sensing line will be In Y1-Y5, the corresponding capacitance change detection is performed only for the horizontal sensing lines Y2 and Y4 related to the candidate contact points P1, P2, P3, and P4, and the processing time of the horizontal sensing lines Y1, Y3, and Y5 is not separately processed. When the step 312 resets the horizontal sensing line Y2 to raise its potential, the vertical sensing lines X1-X5 perform capacitance detection one by one to find the contact point where the capacitance change occurs; the user shown in FIG. 2 According to the contact situation, capacitance changes occur on the vertical sensing lines X2 and X4. When the step 312 resets the horizontal sensing line Y4 to raise its potential, and performs capacitance detection on the vertical sensing lines X1-X5 one by one to find the contact point where the capacitance change occurs, only the vertical sensing line X4 can be sensed. The capacitance on the change does not sense the change in capacitance on the vertical sense line X2 because the candidate contact point P4 is not substantially triggered by the user. After synthesizing the capacitance change results detected by steps 312 and 314, the capacitive touch panel 100 can directly determine that only three (Y2, X2), (Y2, X4), and (Y4, X4) interlaced points are generated. There is a substantial change in capacitance, and no substantial capacitance change is induced at the interlaced point of (Y4, X2); that is, the candidate contact point P4 is culled here among the candidate contact points, and the remaining candidate contact points P1 , P2, P3 will be finally determined as the contact point.

Observing the above description, the detection method disclosed in the present invention uses the self-capacity detection technology in the first stage in addition to the high processing speed of the self-capacity detection technology, and also reduces the amount of data processing in the second stage. Therefore, the mutual capacitance detection technology that requires more processing time can reduce a large amount of unnecessary processing time, and can still detect the accuracy of the contact point by using the mutual capacitance detection technology. In short, the method disclosed by the present invention combines the high processing speed of the self-capacitance detection technology, and greatly reduces the processing time of the mutual capacitance detection technology by eliminating the unnecessary processing data amount, and retains the self-contained detection. The measurement technology accurately detects the characteristics of the contact points to achieve fast real multi-touch technology. In addition, since a large amount of processed data has been eliminated before the second stage, the method shown in FIG. 3 can quickly and accurately lock the user in a capacitive manner even when applied to a large-sized touch panel. The touch point triggered on the touch panel 100.

In addition, although the example in steps 312-316 is to reset the potential of the plurality of candidate contact points in the horizontal sensing lines Y1-Y5, and the vertical sensing lines X1-X5 are detected one by one. In order to obtain the result of the change of the capacitance, in one embodiment of the present invention, the portion of the vertical sensing line X1-X5 that covers the plurality of candidate contact points may be firstly subjected to potential reset, and then the horizontal sensing line Y1. -Y5 detects one by one to get the result of the capacitance change to determine the actual contact point. In steps 302 to 308, although the first stage of capacitance change detection is performed by simultaneously resetting the horizontal sensing lines Y1-Y5 and simultaneously resetting the vertical sensing lines X1-X5, in another aspect of the present invention In the embodiment, the vertical sensing lines X1-X5 may be simultaneously reset and then the horizontal sensing line Y5 is simultaneously reset to perform the first-stage capacitance change detection.

In the second stage of the present invention, in addition to the candidate contact points that are misjudged due to the implementation of the self-capacitance detection method, the candidate contact points may be excluded according to other conditions to further improve the capacitive touch panel detection. Accuracy when touching points. For example, when the user's finger touches the capacitive touch panel, a part of the palm may have the same contact with the capacitive touch panel and trigger a large number of contact points, thereby causing the capacitive touch panel to be judged. mistake. In an embodiment of the present invention, in order to eliminate the contact point between the palm of the user and the capacitive touch panel, the contact point triggered by the finger is also determined, after the end of step 310 in FIG. The candidate contact points adjacent to each other are planned into a plurality of candidate trigger regions, and the palm and the capacitive touch panel are excluded according to the number of candidate contact points covered by the candidate trigger regions and the characteristics directly related to the palm. The generated candidate contact points, wherein all candidate contact points covered by each candidate triggering region have a connected relationship of connected regions. Please refer to FIG. 4 , which is a schematic diagram of generating a plurality of candidate contact point regions on a portion of the capacitive touch panel 100 when the user touches the capacitive touch panel 100 with the palm and the finger, wherein FIG. 4 The contact points on the capacitive touch panel 100 are also based on the representations of Figures 1 and 2, and it is assumed that steps 302-310 shown in Figure 3 have been performed. In addition, for convenience of explanation, the horizontal sensing lines Y1-Y9 and the vertical sensing lines X1-X13 shown in FIG. 4 also cover only one portion of the capacitive touch panel 100. As shown in FIG. 4, when the user touches the capacitive touch panel 100 with the finger and the palm at the same time, the portion of the finger that contacts the capacitive touch panel 100 forms a candidate contact point covering a relatively small number of candidate contact points. The regions R2 and R3, and the portion of the palm contacting the capacitive touch panel 100 form a candidate contact point region R1 covering a relatively large number of candidate contact points, wherein the candidate contact point regions R1, R2, and R3 are each in capacitive touch. Sixteen, nine, and twelve candidate contact points are covered on the panel 100. When performing step 316, a predetermined number of fourteen candidate contact points may be set, and the number of candidate contact points covered or greater than or equal to the predetermined number of candidate contact points is excluded from the last determined contact point; In one case, the sixteen candidate contact points covered by the candidate contact point region R1 in FIG. 4 can be eliminated, and the situation in which the palm is in contact with the capacitive touch panel 100 is eliminated to prevent unnecessary misjudgment.

In addition, when the candidate contact points are determined by the capacitance change in steps 302-316, the capacitance change amount of each candidate contact point may be set to be higher than a predetermined capacitance change amount to make the pressing lighter. Or the candidate contact points caused by the non-user's finger are excluded to prevent the misjudgment of the contact point; wherein the predetermined capacitance change amount may be based on the size of the capacitive touch panel itself or the component distribution density. To decide.

The invention discloses a multi-touch detection method for a capacitive touch panel. The method firstly eliminates the interlaced points that do not need to be sensed by the high processing speed of the self-capacitance detection technology to save unnecessary data, and then implements the candidate generated by the self-capacitance detection technology by the mutual capacitance detection technology. Accurate detection of the contact points to quickly implement real multi-touch, and at the same time solve the problem that the detection of the self-capacitance detection technology in the implementation of the general capacitive touch panel is not accurate enough and the processing speed is over when the mutual capacitance detection technology is implemented. Slow question.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

Capacitive touch panel 100

X1-X13. . . Vertical sensing line

Y1-Y9. . . Horizontal sensing line

P1, P2, P3, P4. . . Candidate touch point

R1, R2, R3. . . Candidate contact point area

302-316. . . step

FIG. 1 is a partial schematic view for explaining a mutual capacitance detecting technology implemented on a capacitive touch panel.

FIG. 2 is a partial schematic diagram for explaining a self-capacitance detection technique performed on a capacitive touch panel.

FIG. 3 is a flow chart of a method for detecting multi-touch on a capacitive touch panel according to the present invention.

FIG. 4 is a schematic diagram of generating a plurality of candidate contact point regions on a portion of the capacitive touch panel when the user touches the capacitive touch panel with the palm and the finger.

302-316. . . step

Claims (6)

A method for detecting a multi-touch on a capacitive touch panel includes: resetting a plurality of first sensing lines of a capacitive touch panel to a first potential; and resetting the plurality of first sensing When the line reaches the first potential, detecting a capacitance change of the plurality of second sensing lines interleaved with the plurality of first sensing lines; resetting the plurality of second sensing lines to a second potential; when resetting the plurality Detecting a change in capacitance of the plurality of first sensing lines when detecting the second sensing line to the second potential; detecting a change in capacitance of the plurality of first sensing lines and a change in capacitance of the plurality of second sensing lines Resulting in a plurality of candidate touch points (Candidate Touch Point); and sequentially resetting the plurality of first sensing lines covering the plurality of candidate contact points, and resetting each of the plurality of candidate contact points covering the plurality of candidate contact points A sensing line detects a change in capacitance of the plurality of second sensing lines to find a plurality of actual contact points from the plurality of candidate contact points. The method of claim 1, wherein the capacitance change of the plurality of first sensing lines is detected, and then the capacitance change of the plurality of second sensing lines is detected. The method of claim 1, wherein the capacitance change of the plurality of second sensing lines is detected, and then the capacitance change of the plurality of first sensing lines is detected. The method of claim 1, further comprising determining whether the number of actual contact points adjacent to each of the plurality of actual contact points is greater than a predetermined number, if the number of adjacent actual contact points of the group is greater than the predetermined number For the number, the actual contact points of the group are rejected by the plurality of actual contact points. The method of claim 1, further comprising determining whether the number of actual contact points adjacent to each of the plurality of actual contact points is greater than a predetermined number, if the number of adjacent actual contact points of the group is greater than or equal to The predetermined number is the actual contact points of the group being culled by the plurality of actual contact points. The method of claim 1, wherein the capacitance change corresponding to the plurality of candidate contact points is higher than a predetermined capacitance change amount.